BHO Thermos Extraction - Points of Concern

[InjectTruth]

Good evening, all. I have been playing with oil here and there, but recently did a larger dry ice kif run, which left me with about a gallon of kif.

I originally was going to simply layer this kif in a parfait fashion with other trim and use in a typical pass through column extraction. However, after reading Jump's thread, skunkpharm research dot com, and some videos on youtube, I've begun thinking about the soak/thermos method.

My original intent was to reduce the volume via the dry ice method, thereby reducing the overall quantity of needed solvent and increasing the efficiency of each can used, hopefully resulting in large plates full of wax like this www.youtube.com/watch?v=_1QWLbGvCpg&feature=related.

Considering all the warnings about butanes explosive nature, I was somewhat shocked to see someone spraying butane into a sealed thermos and allowing it to sit outside for an hour. EVEN MORE shocking was this video of someone substituting a GLASS JAR for the stainless steel thermos http://www.youtube.com/watch?v=VTVRYk0Zdg4&noredirect=1 :facepalm:

Maybe Im a nervous nellie, but that just doesnt seem right to me.

So I am here to ask the oil gurus what are the safety rules for the soak method? So far all I can tell is:

1) Add vent holes to your thermos lid along with your hole for the nozzle

2) Do the process outside

Is that all? Any special precautions for freezing the cans of butane before hand?


And finally, oil masters, is Butane really the ideal way to go for turning a gallon of kif into oil? Or is maybe something like Acetone superior? How about plain old ethanol (especially if the majority of the resulting oil will be used for edibles)?

 

[gunnaknow]

Hey IT, I've been using a thermos flask for extractions since 2006 and the method is very reliable. Someone must have tried the method before me but I appear to be the first to have documented it. If you read posts one and eleven in my 2006 thread, you'll see that the technical name for a thermos is a vacuum flask, or Dewar flask and that they're used in labs to store and transport liquid gases, such as liquid nitrogen. If they can store liquid nitrogen, which has a boiling point of -195.5 C, then they can certainly store liquid butane, which boils at a mere -1 C.

http://www.uk420.com/boards/index.php?showtopic=73723

Glass is also okay to use, providing that it's low thermal expansion glass, like borosilicate glass or pyrex. This is what french coffee presses/cafetieres are made from and people have been using them for butane extractions for years.

So I am here to ask the oil gurus what are the safety rules for the soak method? So far all I can tell is:

1) Add vent holes to your thermos lid along with your hole for the nozzle

2) Do the process outside

Is that all? Any special precautions for freezing the cans of butane before hand?

I'd recommend using protective gloves. Also, avoid metal to metal contact, just incase it causes a spark. The same is true when using other solvents but more so with gaseous solvents. Putting the cans in the freezer is fine. If anything, it would actually decrease the pressure inside the cans.

And finally, oil masters, is Butane really the ideal way to go for turning a gallon of kif into oil? Or is maybe something like Acetone superior? How about plain old ethanol (especially if the majority of the resulting oil will be used for edibles)?

I don't consider myself to be an oil (oleoresin) master but butane isn't the ideal solvent for large amounts of kif. Unless you happen to have a spare gas tank, pump and some technical knowhow. Otherwise, you're better off using solvents that are liquid at room temperature. If you can get food grade n-hexane, that would be considered one of the best liquid state solvents to use. If not, then you could use spectroscopic grade ethanol, >95% grain alcohol, ISO, or acetone but they'll extract more impurities than non polar solvents like butane and hexane. If the resulting oil is to be used in edibles then it's important to use only food grade solvents, like food grade n-hexane, or >95% grain alcohol. With the food grade n-hexane, you need to do a very thorough purge before using in food. With >95% grain alcohol, the purging is much less important.

 

[Gray Wolf]

All good questions, and good info from GK as usual!

Glass would be a poor choice, given the thermal gradients involved, and I prefer stainless, because it is less frangible at low temperatures.

So far the accident that I have repeated time and time again over my lifetime, is to simply drop and break a container, or favorite glass pipe.

Borosilicate is a better choice than glass from a thermal gradient standpoint, and is what most of the lab glassware we use for hazardous material processing, is made of. Many of those hazardous materials come in plain glass containers.

There is no question that using a frangible material like glass increases the risk rate, but you can see what you are doing without x-ray vision using glass, which can also be highly desirable.

We use stainless where we can and just pay real close attention when we handle glass containers of hazardous materials, or our boro glass lab ware.

As for venting, I throw away the thermos plug/cork and drill the injection hole, as well as vent holes in the stainless cap/cup.

It is also important to keep the delta T (temperature differential) between the butane and everything it touches low, to keep the butane in liquid form.

Until it is vaporized, butane has close to zero gas pressure, so two or three vent holes are all that is needed if you freeze the butane can as well. At vaporization, it expands approximately 233:1.

If you don't have enough exhaust hole area, your injection can port will spit backwards at you, if given an opportunity.

I recommend not drilling any more holes than necessary, because while soaking, you want to minimize replacement of the butane enriched atmosphere sitting on top the liquid.

In that equation is the gas mixture, and at those temperatures propane is typically added to the mix, to propel the butane from the can, but as you will be holding the can upside down and injecting downwards, you can slowly pour the butane downwards into the thermos, even if there isn't enough pressure to inject.

If the temperature of both the butane and the system are at -18C/0F when mixed together and the cap/cup left in place, there is very little heat loss from the thermos, so the butane stays liquid for several hours.

I place the thermos in a well ventilated, ignition source free shady spot outdoors, and drape a towel over it to minimize heat losses through convection and air flow blowing through the holes in the cap.

At thirty minutes soak time, the loss of butane is barely noticeable, but present as noted by a few small strings of bubbles. At 1.5 hours soak time, the butane loss is still less than the inch or two covering the material, so no heroic measures are required.

By starting with Kif, you have eliminated many of the reasons for using a non polar solvent, and at low temperatures, butane isn't all that aggressive. I suggest using ethanol.

I used to extract all of our oral meds from bubble, using <95% ethanol, and recycled the alcohol to keep the cost down. It did a great job, but a lot more work, and slower than using recycled butane.

Both the ethanol and butane extractions from bubble, can produce pristine and potent extractions.

The ethanol extract will be more floral than the butane extract, but less so than when compared to QWET extracts directly from prime bud, vis a vis kif.

 

[gunnaknow]

All good questions, and good info from GK as usual!

Cheers GW, you've made an excellent write-up yourself!

 

[jump /injack]

Vent hole size? Drill size?

Vent hole size? Drill size?

Gray Wolf, you say to drill the holes for venting, what size do you recommend? Always a pleasure to read your expertise in what used to be an arcane subject.

 

[Hashmasta-Kut]

what they are doing is essentially no different than storing the butane in its original can, its just a new container..

 

[mack 10]

umm ,interesting stuff, just seen a nice 4.5L thermous flask,at my local supermarket.
it looks like it would hold a good amount of trim. So, anyone got a pic of the cap, showing the evap holes? gives me a better idea of where to drill. how many holes shall i drill? gonna try this out. What sort of yield are you lot getting? (re,is it much better than straight tube blasting?)
Thanks for the info.
mack.

edit; so if i freeze the butane cans and thermos, 3 holes should be enough. just need to see a pic now to see where to drill them.

 

[Gray Wolf]

Gray Wolf, you say to drill the holes for venting, what size do you recommend? Always a pleasure to read your expertise in what used to be an arcane subject.

I use 1/8" for the injection hole and two to four ~1/4" holes for venting. If the material is prefrozen to -18C/0F and the butane is also cold, there is little outgassing.

 

[Gray Wolf]

My picture didn't load because apparently I already have too, too many pictures already posted. Just drill the vent holes in the top of the cup/lid, around the perimeter, with the injection hole in the center.

 

[jump117]

If the material is prefrozen to -18C/0F and the butane is also cold, there is little outgassing.

I think it is only propellent offgasing not butane itself. and only one injecting opening is enough.


My friend tried the sealed mouth of thermos with original cork lid, but the pressure was so small that it does not even knocked it off.

 

[gunnaknow]

Gray Wolf, you say to drill the holes for venting, what size do you recommend? Always a pleasure to read your expertise in what used to be an arcane subject.

If you wish, you can place a jam jar lid with holes in it over the mouth instead. It depends on whether you want to save the flask lid for when you might use the thermos for hot drinks.

what they are doing is essentially no different than storing the butane in its original can, its just a new container..

Obviously it's not pressurized like a can so there is a difference but it's insulating walls are so effective that you can keep the butane in liquid phase for as long as you'd realistically ever need to. It's basically a laboratory technique that we're using. The only difference is that the vacuum flasks used in labs have a small pressure valve, which allows you to store liquid gases for days on end. We don't need more than a few hours at most, however, so we can do without it and save ourselves unnecessary expense.

I think it is only propellent offgasing not butane itself. and only one injecting opening is enough.

How do you mean jump? The butane is the propellent. There's nothing else in the can, besides isobutane and propane sometimes. Propane would boil off the most at first. Although chilling the material and equipment in the freezer helps to reduce the initial boil off, -20°C is above the boiling point of propane. It's also still relatively close to the boiling point of butane, given the fact that it's melting point is <-134°C. Naturally some of it will boil off when it comes into contact with materials at -20°C. This leads to evaporative cooling, as the most energetic molecules are lost and the net temperature then stabilizes.

gunna

 

[jump117]

How do you mean jump? The butane is the propellent. There's nothing else in the can, besides isobutane and propane sometimes.

Speaking of the propellent in this context,
I was referring to iso-butane and propane,
which are added to the gas mixture,
the boiling point of which is substantially lower than that of n-butane,
which provides positive pressure inside the container at temperatures below the boiling point of n-butane,
when butane itself does not creates excessive pressure needed to squeeze it out of the container.

Iso-butane and or propane are the propellents for n-butane.

 

[jump /injack]

Ratio's of plant to butane?

Ratio's of plant to butane?

I use 1/8" for the injection hole and two to four ~1/4" holes for venting. If the material is prefrozen to -18C/0F and the butane is also cold, there is little outgassing.

Will be using safety glasses but still leery of looking down in the thermos with a flash light to see if the plant material is covered; any ball park ratio's for someone faint of heart? How much butane for 1 gram of material. Seems to simple somehow, I must be missing something. This site is like going to BHO University, lots of great professors herein, thank you all.

 

[Avinash.miles]

i shoot butante thru keif all the time, great for your budget, use less tane, also i dont do thermos method, always been happy w using my tubes.

 

[jump117]

Hi, namesake!

No need to unnecessarily demonize refrigerated liquid butane,
it is a quiet fluid, not prone to jumping out of the bottle as a predatory alien.

If you're still scared to look at him,
you can estimate the required amount by comparing the volume
of material poured into a thermos with gas volume, written on the can.

These volumes should be approximately equal.

 

[jump117]

i dont do thermos method, always been happy w using my tubes.

It's great when you have a chance to be even more happy!

( especially in a thread titled "BHO Thermos Extraction - Points of Concern")

 

[gunnaknow]

Speaking of the propellent in this context,
I was referring to iso-butane and propane,
which are added to the gas mixture,
the boiling point of which is substantially lower than that of n-butane,
which provides positive pressure inside the container at temperatures below the boiling point of n-butane,
when butane itself does not creates excessive pressure needed to squeeze it out of the container.

Iso-butane and or propane are the propellents for n-butane.

Oh, if you were referring to the isobutane and propane as propellents then I agree. I thought that you meant something else besides the butane mixture. Yes, the propane will be the first to boil off, although obviously not as pure propane.

 

[gunnaknow]

Jump, I understand what you were getting at but I wouldn't have said that propane and isobutane are the propellents for n-butane. Atleast not in normal operating conditions. That could make it sound as though n-butane is the intended product for delivery and that the propane and isobutane are just added to help deliver the n-butane. I know that this isn't what you intended to mean. The truth is that all three are the propellents and they are used as a mixture because their combined vapor pressure works better together, for their intended application. Pure propane isn't suitable for use in certain products because of it's high vapor pressure and the requirement for robust containers. Pure n-butane isn't suitable for certain applications because it stops working as a propellent below -0.5C. A mixture of the two provides a good compromise for manufacturers.

By chilling the canisters down to around -20°C, we're altering the behavior of the mixture however, as the n-butane and isobutane will no longer behave as propellents, at 1 atmosphere. So we could refer to the propane as the sole propellent but only because we've changed the dynamics by chilling the cans. In an upright position, this would lead to the propane becoming depleted long before the isobutane and n-butane, leaving the can still half full and unusable, until the can temperature warmed up. However, the fact that we're injecting the gas downwards negates that problem. I'm digressing a little though. The main point is that all three are the propellents, in typical operating conditions. The point that you were getting at was correct though, which was that the propane and to a lesser extent the isobutane, will make up the majority of the initial boil off. I do enjoy our conversations.

gunna

 

[InjectTruth]

Thank you all for chiming in. I have been quite busy and haven't picked up a steel thermos yet. Very glad to see all these helpful hints and extra tidbits concerning this method. I think it will work perfectly for my application.

 

[jump /injack]

Hashmasta-Kut, jump 117, Gray Wolf, gunnaknow/ some good questions and fast answers, can't get better information about something in particular than this. Everything you wanted to know about vacuum flask extraction but didn’t know the questions to ask or the people to ask them of; thanks for the expertise, you're the greatest.